Toluic acid

ABSTRACT

Process for oxidatively carbonylating toluene to toluic acid, at least 50 mol % of the toluic acid being the p-isomer, said process comprising contacting and reacting, at 110°-250° C., at a pressure of at least 500 psi (3.45 MPa), toluene, carbon monoxide, oxygen and the catalyst ingredients consisting essentially of 
     (a) a compound of rhodium, iridium, ruthenium, platinum, palladium or osmium; 
     (b) a sulfur oxy-acid or a Group Ia or IIa metal salt of a sulfur oxy-acid; and 
     (c) an acid or acid mixture having a Hammett acidity value (--H o ) of greater than 7.0, 
     said catalyst ingredients containing 0.5-30 mol % of (a) and 70-99.5 mol % of (b+c), with the molar ratios of (b/a) and (c/a) each being at least 2, and recovering toluic acid.

CROSS-REFERENCE TO RELATED APPLICATIONS

This is a division of application Ser. No. 215,712 filed Dec. 15, 1980,now U.S. Pat. No. 4,356,318, as a continuation-in-part of applicationSer. No. 174,920, filed Aug. 4, 1980, which is a continuation-in-part ofapplication Ser. No. 108,819, filed Dec. 31, 1979. The two earliestfiled applications have been abandoned.

DESCRIPTION TECHNICAL FIELD

This invention relates to the oxidative carbonylation of aromaticcompounds, for example, the preparation of toluic acids from toluene,carbon monoxide and oxygen.

BACKGROUND

The oxidative carbonylation of aromatic compounds to aromatic carboxylicacids is well known in the art. U.S. Pat. No. 3,700,729 discloses thecatalytic liquid phase process comprising contacting an aromaticcompound and carbon monoxide in a substantially anhydrous organic liquidreaction medium which is inert to the reactants and the catalyst whichis a halide salt of a Group VIII metal in its highest oxidation state,continuing the contacting until the catalyst is reduced to a lowervalence state and the aromatic compound is oxidatively carbonylated, andthereafter hydrolyzing the carbonylated compound to the aromaticcarboxylic acid. The patent exemplifies the conversion of toluene top-toluic acid. U.S. Pat. No. 3,920,734 discloses a process for preparingan aromatic carboxylic acid from an aromatic compound by means of carbonmonoxide, oxygen and a palladium carboxylate catalyst. The patentexemplifies the conversion of toluene to a mixture of toluic acidisomers. U.S. Pat. No. 4,093,647 discloses a process for preparing anaromatic carboxylic acid from an aromatic compound of the benzene seriesby means of carbon monoxide and an inorganic salt mixture consisting ofa major amount of a thallium salt and a minor amount of a palladiumsalt. The patent exemplifies the formation of a mixture of toluic acidisomers, predominantly the p-isomer, from toluene.

The acid-catalyzed carbonylation of aromatic compounds to form aldehydesis known in the art. Chem Systems, Inc., Process Evaluation and ResearchPlanning Report, 2nd quarter, 1976, discloses the HF/BF₃ catalyzedcarbonylation of toluene to tolualdehyde which can be converted toterephthalic acid by a liquid phase oxidation. A similar disclosure asto the formation of tolualdehyde is made in British Pat. No. 1,485,816.Japanese Publication No. J5 1146-430 based on Japanese Patentapplication No. 070587 discloses the formation of tolualdehyde from thereaction of toluene and carbon monoxide in the presence oftrifluoromethanesulfonic acid (often referred to as triflic acid) in ananhydrous state or in combination with a Lewis acid.

It is an object of this invention to provide a catalytic liquid phaseprocess for producing toluic acids from toluene. A further object is toprovide such a process whereby at least 50 mol % of the toluic acidsproduced is p-toluic acid. Other objects will become apparenthereinafter.

DISCLOSURE OF INVENTION

For further comprehension of the invention, and of the objects andadvantages thereof, reference may be made to the following descriptionand to the appended claims in which the various novel features of theinvention are more particularly set forth.

The invention resides in a process for preparing toluic acids, at least50 mol % of which is p-toluic acid, by means of a catalytic oxidativecarbonylation reaction from toluene, oxygen and carbon monoxide. Morespecifically, the process of the invention resides in contacting andreacting toluene, carbon monoxide, oxygen and the catalyst ingredientsconsisting essentially of

(a) a compound of rhodium, iridium, ruthenium, platinum, palladium orosmium;

(b) a sulfur oxy-acid or a Group Ia or IIa metal salt of a sulfuroxy-acid; and

(c) an acid or acid mixture having a Hammett acidity value (--H_(o)) ofgreater than 7.0,

said catalyst ingredients containing 0.5-30 mol % of (a) and 70-99.5 mol% of (b+c), with the molar ratios (b/a) and (c/a) each being at least 2,preferably at least 3, most preferably at least 4, and recovering toluicacid.

Included under (c) are strong sulfur oxy-acids such as, for example,sulfuric acid (--H_(o) of 11), oleum and certain sulfonic acids whichare also suitable for use under (b). Although not wishing to be bound bythis explanation, it is thought that the active catalyst for theoxidative carbonylation reaction consists of one or more ionic speciesof sulfate or sulfonate of an above-listed Group VIII metal, formed bythe partial or complete replacement of the anions or ligands of thestarting Group VIII metal compound with anions from a sulfur oxy-acid orsalt thereof, in the presence of strong acid of --H_(o) greater than7.0. Evidence for the formation of ionic sulfonates in the reaction of arhodium compound with a sulfur oxy-acid is provided hereinafter inExample 30. Further evidence is provided in the Procedure for CatalystPreparation using Nafion® Perfluorosulfonic Acid Resin described belowwherein a reaction between rhodium trichloride and the polymericsulfonic acid is followed by titration of the liberated hydrochloricacid and by analysis of rhodium chemically bound to the polymer. Otherexamples summarized in Table 3, infra, confirm the operability of themetal salts of sulfur oxy-acids and the requirement of strong acid incombination with the Group VIII metal sulfur-oxy compound as thecatalyst in the oxidative carbonylation process of the invention.

As already suggested, the Group VIII metal compound which is used ascatalyst ingredient (a) can be any Group VIII metal compound capable ofcombining chemically with a sulfur oxy-acid or its metal salt. Examplesof such compounds include the rhodium acetate, trifluoroacetate,chloride and nitrate, the rhodium carbonyls Rh₆ (CO)₁₆ and RhH(CO)(Pφ₃)₃, where φ is phenyl, iridium chloride, ruthenium chloride,platinum chloride, osmium chloride and palladium nitrate. Examples ofsuitable sulfur oxy-acids include sulfuric acid; oleum; fluorosulfonicacid; α-fluorosulfonic acids, including trifluoromethanesulfonic acid(triflic acid), perfluorooctanesulfonic acid, and CF₃ CF₂ OCF₂CF(CF₃)OCF₂ CF₂ SO₃ H (perfluoro-4-methyl-3,6-dioxaoctanesulfonic acid);methanesulfonic acid; benzenesulfonic acid; and p-toluenesulfonic acid.Examples of acids suitable for use as catalyst component (c) include theabove sulfur oxy-acids which have an --H_(o) of greater than 7.0,hydrofluoric acid and mixtures of hydrofluoric acid and antimonypentafluoride. Such acids are described further by Olah et al. inScience, 206, 13 (1979).

Preferred catalysts in the process of this invention provide toluicacids, at least 70 mol % of which is p-toluic acid, and include thosewherein catalyst ingredient (a) is a compound of rhodium, iridium orruthenium. Especially preferred catalysts provide toluic acids, at least85 mol % of which is p-toluic acid, and include those wherein catalystingredient (a) is a compound of rhodium or iridium and catalystingredients (b) and (c) are the same and consist of a sulfur oxy-acidhaving an --H_(o) greater than 7.0.

Sufficiently strong, that is, having an --H_(o) of greater than 7.0,polymeric sulfonic acids also can be used in the process of theinvention. Such acids are comprised of polymeric materials havingsulfonic acid groups attached to the polymer structure. Representativeof such a sulfonic acid is a perfluorinated polymeric sulfonic acid.Nafion® Perfluorosulfonic Acid Products represent commercially availablematerials of this type. The use of Nafion® as a strong acid is describedin J. Org. Chem., 42, 4187 (1977) and 43, 3142 and 3147 (1978) in aseries of papers by Olah et al. and Kaspi et al. and entitled"Heterogeneous Catalysis By Solid Superacids." It should be understoodthat the polymeric sulfonic acids useful in this invention normallyprovide catalyst ingredients (b) and (c). If, however, the sulfonic acidsites in the polymer have been largely or completely neutralized, i.e.,converted to the salt form by the addition of a salt or hydroxide of aGroup Ia or IIa metal (see below and Table 1), only catalyst ingredient(b) is provided by the polymer and a strong acid ingredient (c) must beadded to obtain an operable catalyst. It will be obvious to one skilledin the art that when at least 0.5 mol % of the sulfonic acid orsulfonate salt sites in the polymer have reacted with the catalyticallyactive Group VIII metal ions, catalyst ingredient (a) is also providedby the polymer. Catalysts prepared herein from a polymeric sulfonic acidare referred to as heterogeneous catalysts. Those prepared herein fromthe nonpolymeric sulfonic acid are referred to as homogeneous catalysts.

Included in this invention are perfluorinated polymeric sulfonic acidshaving, based on the sulfonic acid groups, about 5 to 98.5 mol % ofhydrogen ions and 1.5 to about 95 mol % of rhodium, iridium, ruthenium,platinum, palladium or osmium ions. Preferred polymeric sulfonic acidshave 50 to 98.5 mol % of the hydrogen ions and 1.5 to 50 mol % of theGroup VIII metal ion. Also included in this invention are perfluorinatedpolymeric sulfonate salts having, based on the sulfonate groups, about 5to 98.5 mol % of Group Ia or Group IIa metal ions and 1.5 to about 95mol % of rhodium, iridium, ruthenium, platinum, palladium or osmiumions.

The process of the invention is carried out at 110°-250° C., preferably130°-200° C. At below 110° C. the reaction proceeds, but at slow rates.There is little, if any, advantage in operating the process above 250°C. Particularly if any catalyst component is a thermally unstablematerial, for example, as are some polymeric sulfonic acids, the upperlimit of reaction temperature must be selected accordingly.

Although the reaction pressure is not critical to the process of theinvention, generally it should be at least 500 psi (3.45 MPa). The upperlimit of pressure is usually governed by the cost of the equipmentneeded to contain the reactant materials.

Preferably, in order to avoid the use and handling of an explosivereaction mixture, the amount of oxygen introduced into the system shouldnot exceed 7.5 mol % of the combined amounts of carbon monoxide andoxygen in the system. If the reaction is carried out in a batch typeoperation, for example, in an autoclave, it may be desirable, in orderto maintain the lowest possible level of oxygen, to introduce theinitial charge of toluene and carbon monoxide before adding the oxygen.Carbon monoxide can then be added subsequently in such amounts as isnecessary to maintain the desired reaction pressure as carbonylationtakes place.

As is already evident from the above description, the reaction can becarried out in a batchwise or continuous mode of operation in a systemwhich can be either homogeneous or heterogeneous, depending on whetheror not the catalyst is soluble in the reaction medium. Although asolvent or liquid medium which is inert to oxidative carbonylation canbe present during the reaction, it is not necessary in the process ofthe invention since the toluene itself serves as a solvent or liquidmedium. Workup of the toluic acid from the reaction mixture can becarried out by conventional means. Heterogeneous catalyst can be removedby filtration of the reaction mixture. When a soluble catalyst is used,that is, when the system is homogeneous, the reaction mixture can bediluted with methylene chloride and extracted with aqueous sodiumchloride, after which the methylene chloride layer can be evaporated torecover the toluic acid.

EXAMPLES

In the following examples, the toluic acids which were produced wereconverted to trimethylsilyl esters by conventional techniques and thenanalyzed by means of standard gas chromatographic procedures.

PROCEDURE FOR CATALYST PREPARATION USING NAFION® PERFLUOROSULFONIC ACIDRESIN

The heterogeneous catalysts were prepared by stirring an aqueoussolution of a soluble compound of an above-listed Group VIII metal (forexample, the nitrate or chloride) with Nafion® (H⁺) (of equivalentweight 1100) either until the supernatant of the resultant slurry wascolorless or for such time as was necessary to convert the desirednumber of acidic sites in the Nafion® (H⁺) to the Group VIII metal salt.The formation of the Group VIII metal salt can be followed by titratingthe acid (for example, nitric acid or hydrochloric acid) liberated inthe supernatant of the slurry. A specific example of the procedurefollows.

Forty-five g of Nafion® (H⁺) containing 41 mmols of sulfonic acid groupsin 450 ml of H₂ O was stirred with 0.78 g of RhCl₃.xH₂ O (x is about 3)at 95° C. for about 100 h. The resultant slurry was filtered and theorange resin was dried in a vacuum oven for about 3 h at about 100° C.The filrate was titrated for liberated hydrochloric acid (6.3 mmols ofHCl), and the resin was analyzed for rhodium (0.47 wt % Rh,corresponding to 2.0 mmols of Rh). The catalyst thus prepared contains##EQU1## The mold % (a) of rhodium compound in the catalyst ingredients,as calculated by the formula given above Table 1, is ##EQU2##

Nafion® (H⁺) may be converted to a salt form, e.g., the Na salt, by asimilar procedure wherein the resin is treated with an aqueous solutionof sodium chloride or sodium nitrate. The salt form may be furthertreated with a water-soluble rhodium, iridium, platinum, ruthenium,palladium or osmium compound to replace the desired number of Na ionswith the Group VIII metal ion.

Alternatively, Nafion® (H⁺) may be converted substantially to the GroupVIII metal salt by either of the above techniques, and an appropriatestrong acid may be added to provide the necessary catalyst ingredients(b) and/or (c), as discussed above.

PROCEDURE FOR SHAKER TUBE EXPERIMENT WITH HETEROGENEOUS CATALYST FROMNAFION®

In a typical experiment, a shaker tube was flushed with N₂, charged withthe catalyst prepared as described above, cooled, evacuated and chargedwith 120 ml of toluene. The tube was sealed and heated to reactiontemperature. Carbon monoxide, then oxygen, and then more carbon monoxidewas introduced into the tube until the desired pressure was reached. Themol fraction of oxygen was 0.075. During the reaction time of two hours,the tube was repressurized with carbon monoxide as necessary to maintainpressure during carbonylation. After the tube was discharged, thecatalyst was removed by filtration and the filtrate was analyzed fortoluic acids.

PROCEDURE FOR SHAKER TUBE EXPERIMENT WITH HOMOGENEOUS (SOLUBLE) CATALYST

In a typical experiment, a shaker tube is flushed with N₂, charged withan appropriate Group VIII metal compound (a), cooled, evacuated andcharged with a suitable sulfur oxy-acid or metal salt thereof (b), asuitable acid or acid mixture having an --H_(o) of greater than 7.0 (c),and, finally, 80 ml of toluene. Alternatively, the Group VIII metalcompound can be reacted separately with excess sulfur oxy-acid or metalsalt thereof and then charged to the shaker tube in place of the firsttwo ingredients described above. After being charged the tube is sealedand heated to reaction temperature. Carbon monoxide, then oxygen, andthen more carbon monoxide is introduced into the tube until the desiredpressure is reached. The mol fraction of oxygen is no greater than0.075. During the reaction time of two hours, the tube is repressurizedwith carbon monoxide as necessary to maintain pressure duringcarbonylation. The tube is discharged of the liquid contents. Thesolution is diluted with CH₂ Cl₂ and extracted with saturated aqueousNaCl solution. The organic phase is dried over MgSO₄, concentrated to asmall volume, and then analyzed for toluic acids.

EXAMPLE 1-29

These examples represent various embodiments of the process of theinvention, carried out using the procedures outlined above. Appropriatedata for the examples using the heterogeneous catalyst are summarized inTable 1, for the examples using the homogeneous catalyst, in Tables 2and 3. At the end of each table are provided data relative toexperimental showings (S) which were carried out to compare the processof the invention as claimed herein with similar processes outside theinvention.

For the heterogeneous systems, Experiments S1 and S2 (Table 1) show thatno reaction occurs when the catalyst lacks ingredient (a). S5 shows thatingredient (c) is also essential for reaction. S3 and S4 illustrate theimportance of oxygen and sufficiently high temperature in the process ofthis invention.

For the homogeneous systems, Experiments S6-S11 (Table 2) show thatcatalyst ingredient (b) is essential for reaction. S6-S8 also lackingredient (c), as do S13 and S14 (Table 3); acetic, trifluoroacetic andhydrochloric acids do not meet the requirements of ingredient (c) asdefined above. S12 confirms that ingredient (a) is essential forreaction.

The difference between the mol % Group VIII metal compound (col. 4 ofTables 1-3), i.e., the amount of catalyst ingredient (a), and 100 mol %represents the mol % of catalyst ingredients (b)+(c). In Exanples 1-24(Tables 1 and 2), ingredients (b) and (c) are provided by the samecompound; in Examples 25-29 (Table 3), mol % of ingredient (b), i.e.,CF₃ SO₃ Na, is listed.

The mol % of Group VIII metal compound in the catalyst ingredients iscalculated using the formula ##EQU3## where (a), (b) and (c) are thecatalyst ingredients defined as above.

The experiments which are summarized in Table 3 were carried out at 150°C. and 27.6 mPa.

                  TABLE 1                                                         ______________________________________                                        Heterogeneous Catalyst                                                        Pre-                                                                          pared                                                                         Cata-    Resin   Mol                Mol % Isomer                              lyst     Compd   %      Temp  P     Distribution                              No.  Wt (g)  Form    Rh   (°C.)                                                                        (MPa) o    m    p                             ______________________________________                                        1    4       H.sup.+ 6.3  150   27.6  1    7    92                            2    3       H.sup.+ 9.5  120   27.6  0.1  8.4  91.5                          3    7.4     H.sup.+ 6.8  150   34.5  0.7  5.7  93.6                          4    4       H.sup.+ 12.9 150   13.8  9.8  8.5  90.7                          5    4       H.sup.+ 12.9 150   6.9   0.8  9.2  90                            6    4       H.sup.+ 12.7 150   3.45  1.2  8.7  90                            7    4       H.sup.+ 12.9 150   27.6  1    8    91                            8    4       H.sup.+ 14.5 150   27.6  1.5  12.5 86                            9    4       H.sup.+ 25.3 150   27.6  1.6  12.7 85.7                          S1   4       H.sup.+ 0    150   27.6  Nil  Nil  Nil                           S2   4       Na.sup.+                                                                              0    150   27.6  Nil  Nil  Nil                           S3   4       H.sup.+ 12.9 150   27.6* Nil  Nil  Nil                           S4   4       H.sup.+ 12.9 100   27.6  [ ←                                                                           trace                                                                              → ]                    S5   4       Na.sup.+                                                                              6.2  150   27.6  Nil  Nil  Nil                           ______________________________________                                         *without oxygen                                                          

                                      TABLE 2                                     __________________________________________________________________________    Homogeneous Catalyst                                                                           Group                                                                             Mol %                                                                     VIII                                                                              Group                                                                     Metal                                                                             VIII        Mol % Isomer                                 Ex.              Compd                                                                             Compd                                                                             Temp.                                                                             P   Distribution                                 No.                                                                              Catalyst Components                                                                         Wt (g)                                                                            Metal                                                                             (°C.)                                                                      (MPa)                                                                             o  m  p                                      __________________________________________________________________________    10 RhCl.sub.3 /CF.sub.3 SO.sub.3 H                                                             0.3 4.8 150 27.6                                                                              1.9                                                                              5.7                                                                              92.4                                   11 Rh(NO.sub.3).sub.3 /CF.sub.3 SO.sub.3 H                                                     0.1 2.8 150 27.6                                                                              0.6                                                                              6.0                                                                              93.0                                   12 Rh(NO.sub.3).sub.3 /CF.sub.3 SO.sub.3 H                                                     0.3 4.2 150 16.6                                                                              3.2                                                                              6.2                                                                              90.7                                   13 Rh(NO.sub.3).sub.3 /C.sub.8 F.sub.17 SO.sub.3 H                                             0.1 3.2 150 27.6                                                                              0.5                                                                              8.5                                                                              91.0                                   14 Rh(NO.sub.3).sub.3 /CF.sub.3 CF.sub.2 OCF.sub.2                                             0.3 8.6 150 27.6                                                                              2.7                                                                              5.8                                                                              92.0                                       ##STR1##                                                                  15 Rh(NO.sub.3).sub.3 /CH.sub.3 SO.sub.3 H                                                     0.2 2.1 150 27.6                                                                              1.4                                                                              6.2                                                                              92.4                                   16 Rh(NO.sub.3).sub.3 /FSO.sub.3 H                                                             0.2 1.9 150 27.6                                                                              0.6                                                                              4.8                                                                              94.5                                   17 Rh(NO.sub.3).sub.3 /H.sub.2 SO.sub.4                                                        0.2 1.7 150 27.6                                                                              0.7                                                                              7.3                                                                              92.0                                   18 Rh(NO.sub.3).sub.3 /p-CH.sub.3 C.sub.6 H.sub.4 SO.sub.3 H                                   0.2 6.3 150 27.6                                                                              2.2                                                                              8.4                                                                              89.3                                   19 Rh(NO.sub.3).sub.3 /C.sub.6 H.sub.5 SO.sub.3 H                                              0.3 3.5 150 27.6                                                                              1.0                                                                              8.4                                                                              90.6                                   20 Rh.sub.6 (CO).sub.16 /CF.sub. 3 SO.sub.3 H                                                  0.5 2.0 150 27.6                                                                              1.5                                                                              7.5                                                                              91.0                                   21 Rh.sub.6 (CO).sub.16 /CH.sub.3 SO.sub.3 H                                                   0.4 1.2 150 27.6                                                                              0.6                                                                              7.8                                                                              91.6                                   22 RhH(CO)(Pφ.sub.3).sub.3 /CF.sub.3 SO.sub.3 H                                            1.0 4.6 150 27.6                                                                              1.7                                                                              11.9                                                                             86.4                                   23 [Rh(O.sub.2 CCH.sub.3).sub.2 ].sub.2 /CF.sub.3 SO.sub.3 H                                   0.4 3.8 150 27.6                                                                              2.0                                                                              9.0                                                                              89.0                                   24 PtCl.sub.2 /CF.sub.3 SO.sub.3 H                                                             0.3 4.9 150 27.6                                                                              15.0                                                                             20.0                                                                             65.0                                   S6 [Rh(O.sub.2 CCH.sub.3).sub.2 ].sub.2 /CH.sub.3 CO.sub.2 H                                   0.3 1.9 150 27.6                                                                              Nil                                                                              Nil                                                                              Nil                                    S7 [Rh(O.sub.2 CCF.sub.3).sub.2 ].sub.2 /CF.sub.3 CO.sub.2 H                                   0.3 1.6 150 27.6                                                                              Nil                                                                              Nil                                                                              Nil                                    S8 Rh(NO.sub.3).sub.3 /CF.sub.3 CO.sub.2 H                                                     0.3 0.7 150 27.6                                                                              Nil                                                                              Nil                                                                              Nil                                    S9 RhCl.sub.3 /HF                                                                              0.3 1.1 150 27.6                                                                              Nil                                                                              Nil                                                                              Nil                                    S10                                                                              RhCl.sub.3 /SbF.sub.5 */HF*                                                                 0.3 1.0 150 27.6                                                                              Nil                                                                              Nil                                                                              Nil                                    S11                                                                              Rh(NO.sub.3).sub.3 /HF                                                                      0.3 0.9 150 27.6                                                                              Nil                                                                              Nil                                                                              Nil                                    S12                                                                              CF.sub.3 SO.sub.3 H                                                                         0   0   150 27.6                                                                              Nil                                                                              Nil                                                                              Nil                                    __________________________________________________________________________     *0.00922 mol SbF.sub.5, 0.1 mol HF                                       

                                      TABLE 3                                     __________________________________________________________________________    Homogeneous Catalyst                                                                         Group VIII                                                                           Mol %                                                                  Metal  Group VIII   Mol % Isomer                               Ex.                                                                              Catalyst    Compd. Compd  Mol % Distribution                               No.                                                                              Components  wt (g) Metal  CF.sub.3 SO.sub.3 Na                                                                o  m  p                                    __________________________________________________________________________    25 Rh(NO.sub.3).sub.3 /                                                                      0.3    0.9    4.9   1.7                                                                              14.6                                                                             83.7                                    CF.sub.3 SO.sub.3 Na/HF                                                    26 Rh(NO.sub.3).sub.3 /                                                                      0.3    0.9    4.9   1.5                                                                              11.5                                                                             87.0                                    CF.sub.3 SO.sub.3 Na/SbF.sub.5 */HF*                                       27 IrCl.sub.3 /CF.sub.3 SO.sub.3 Na/                                                         0.4    4.5    19.6  1.2                                                                              11.0                                                                             87.8                                    CF.sub.3 SO.sub.3 H                                                        28 Pd(NO.sub.3).sub.2 /CF.sub.3 SO.sub.3 Na/                                                 0.4    5.2    16.2  32.0                                                                             16.0                                                                             52.0                                    CF.sub.3 SO.sub.3 H                                                        29 RuCl.sub.3 /CF.sub.3 SO.sub.3 Na/                                                         0.4    6.3    19.2  10.0                                                                             18.0                                                                             72.0                                    CF.sub.3 SO.sub.3 H                                                        S13                                                                              Rh(NO.sub.3).sub.3 /CF.sub.3 SO.sub.3 Na/                                                 0.3    14.9.sup.+                                                                           85.0  Nil                                                                              Nil                                                                              Nil                                     HCl                                                                        S14                                                                              Rh(NO.sub.3).sub.3 /CF.sub.3 SO.sub.3 Na                                                  0.3    24.0.sup.+                                                                           76.0  Nil                                                                              Nil                                                                              Nil                                  __________________________________________________________________________     *0.00922 mol SbF.sub.5, 0.1 mol HF                                            ##STR2##                                                                 

EXAMPLE 30

A sample of Rh(OH)₃ H₂ O, prepared from RhCl₃.3H₂ O by the procedure ofBasolo, Inorganic Syntheses, VII, page 214, was reacted without externalheating with a 3:1 molar excess of trifluoromethanesulfonic acid.Unreacted acid was distilled off under reduced pressure and areddish-brown solid was recovered. Infrared analysis of the solid showedcharacteristic bands at 1250 cm⁻¹, 1176 cm⁻¹ and 1030 cm⁻¹, closely,similar to the trifluoromethanesulfonate ion (CF₃ SO₃ ⁻) bands observedin various metal salts of trifluoromethanesulfonic acid by Gramstad andHaszeldine, J. Chem. Soc., 173 (1956), Haszeldine & Kidd, J. Chem. Soc.,4228 (1954), and Batchelor et al., Inorg. Chem., 16, 1414 (1977).

0.3 g of the rhodium trifluoromethanesulfonate product prepared abovewas substituted for the rhodium or iridium compound and the sulfuroxy-acid in the procedures outlined for Examples 1-29. In oneexperiment, (i), no acid was added; in second and third experiments (ii)and (iii), trifluoroacetic acid and trifluoromethanesulfonic acid,respectively, were added in such amounts that the mixtures of rhodiumcompound and acid contained: (ii) 2.0 mol % rhodium compound, 98.0 mol %trifluoroacetic acid; and (iii) 2.4 mol % rhodium compound, 97.6 mol %trifluoromethanesulfonic acid. Both experiments were run at 150° C. and27.6 MPa with the following results being obtained:

                  TABLE 4                                                         ______________________________________                                        Mol % Isomer Distribution                                                            o           m      p                                                   ______________________________________                                        (i)      Nil           Nil    Nil                                             (ii)     Nil           Nil    Nil                                             (iii)    2.0           9.0    89.0                                            ______________________________________                                    

EXAMPLE 31

A 300 cc Hastelloy C autoclave equipped with separate gas and liquidinlet lines, thermocouple, stirrer, cooling coils and an overflow diptube was charged with 125 ml of toluene and 30 g of Nafion® (H⁺, Rh⁺³)(10.4 mol % metal cation). The autoclave was heated to 150° C. andpressured to 4000 psi (27.6 MPa) with a gaseous mixture of oxygen andcarbon monoxide (mol % of O₂ is 3%). Toluene and the gaseous mixturewere fed at a rate of 3.0 ml/min and 2200 cc/min, respectively. Productwas continously discharged through the dip tube and through a gas-liquidseparator, and the liquid was collected. During the four hours ofoperation, the stirring rate was maintained at 500 RPM. Analysis of thecollected liquid showed the presence of 94.4% of the p-toluic acidisomer. The conversion of toluene was 1%.

EXAMPLE 32 A. Preparation of Palladium-Exchanged Nafion® (H⁺) Resin

Twenty two g of Nafion® (H⁺) containing 20.0 mmols of sulfonic acidgroups in 300 ml of H₂ O was stirred with 2.63 g of Pd(NO₃)₂.xH₂ O (39.0wt % Pd; 9.7 mmols of Pd) at 60° C. for about 5 h. The resultant slurrywas filtered and the reddish-brown resin was dried in a vacuum oven forabout 5 h at about 110° C. The clear filtrate was titrated for liberatednitric acid (18.5 mmols of HNO₃), and the resin was analyzed forpalladium (3.95 wt % Pd, corresponding to 8.5 mmols of Pd). Mol % ofpalladium in the resin composition was: ##EQU4## Hydrogen ions comprisedthe remainder (15.0 mol %), the total amounting to 100 mol %. The mol %of palladium compound in the starting ingredients (to prepare the resin)was: ##EQU5##

B. Preparation of Heterogeneous Catalyst and Toluic Acid

A palladium-exchanged Nafion® (H⁺) resin was prepared as in Part A andcontained at least 95 mol % palladium. Eight g of this resin containing4.3 mmols of palladium, 6.76 g (45.0 mmols) of trifluoromethanesulfonicacid, and 80 ml of toluene were charged to a shaker tube previouslyflushed with nitrogen. The tube was pressurized with 200 psi (1.38 MPa)of a mixture of CO and O₂ (3 mol % O₂), and the temperature wasincreased to 150° C. A total pressure of 4000 psi (27.6 MPa) was reachedby continuing to pressurize the shaker tube to 800 psi (5.5 MPa) with aCO/O₂ mixture, followed by 180 psi (1.24 MPa) oxygen and 3020 psi (20.8MPa) of a CO/O₂ mixture. During the reaction time of two hours, the tubewas repressurized with a CO/O₂ mixture as necessary to maintainpressure. After the reaction, the tube was discharged, the resin wasremoved by filtration and the filtrate was diluted with methylenechloride and washed with water. The organic phase was dried over MgSO₄,evaporated to a small volume, and analyzed for toluic acids with thefollowing results:

    ______________________________________                                        Mol % Isomer Distribution                                                     o               m      p                                                      ______________________________________                                        29.0            16.0   55.0                                                   ______________________________________                                    

The mol % of Pd compound in the catalyst ingredients was ##EQU6##

The experiment described above was repeated except thattrifluoromethanesulfonic acid was omitted. Toluic acids were formed inapproximately 3% of the amount obtained above.

    ______________________________________                                        Mol % Isomer Distribution                                                     o               m      p                                                      ______________________________________                                        34.0            27.0   39.0                                                   ______________________________________                                    

EXAMPLE 33

Twenty-two g of Nafion® (H⁺) containing 20.0 mmols of sulfonic acidgroups in 300 ml of H₂ O was stirred with 2.2 g of Rh(NO₃)₃.2H₂ O (6.8mmols) at 60° C. for about 67 h. The resultant slurry was filtered andthe orange resin was dried in a vacuum oven for about 5 h at about 110°C. The filtrate was titrated for liberated nitric acid (5.6 mmols) andthe resin was analyzed for rhodium (2.6 mmols). The results show thatthe catalyst composition contained 15.3 mol % rhodium ions and 84.7 mol% hydrogen ions. The mol % of rhodium compound in the catalystingredients was 25.4 mol % (Compare Example 9, Table 1, wherein the mol% Rh was 25.3).

BEST MODE FOR CARRYING OUT THE INVENTION

The best mode for carrying out the process of the invention is believedto be demonstrated by Examples 3 and 11 (batchwise) and 31 (continuous).

INDUSTRIAL APPLICABILITY

Toluic acid, particularly p-toluic acid, is a useful intermediate in thepreparation of terephthalic acid which is used in the manufacture offiber-forming polyesters.

Although the preferred embodiments of the invention have beenillustrated and described, it is to be understood that there is nointent to limit the invention to the precise consructions hereindisclosed and that the right is reserved to all changes andmodifications within the scope of the invention as defined in theappended claims.

I claim:
 1. Perfluorinated polymeric sulfonic acid having, based on thesulfonic acid groups, about 5 to 98.5 mol % of hydrogen ions and 1.5 toabout 95 mol % of rhodium, iridium, ruthenium, platinum, palladium orosmium ions.
 2. Perfluorinated polymeric sulfonic acid having, based onthe sulfonic acid groups, 50 to 98.5 mol % of hydrogen ions and 1.5 to50 mol % of rhodium, iridium, ruthenium, platinum, palladium or osmiumions.
 3. Perfluorinated polymeric sulfonate salt having, based on thesulfonate groups, about 5 to 98.5 mol % of Group Ia or Group IIa metalions and 1.5 to about 95 mol % of rhodium, iridium, ruthenium, platinum,palladium or osmium ions.